Just bought the game on GOG. Running under Mac OS 10.11.6.
The game runs fine while playing. When I complete a "My Pet Dungeon" level, it allows me to progress to the next level. But if I close the game and then reopen, all MPD progress is lost and I have to start at the beginning.
Possibly related: I am unable to load save games in campaign mode. I can create them, but when I select them from the menu and hit "load", nothing happens. However, it does register completed levels in campaign mode - although I can't restore from within a level, it doesn't take me back to the beginning of the campaign.
Customer support service by UserEcho